A Method for Determining Residual Stresses in Pipes

1982 ◽  
Vol 104 (3) ◽  
pp. 223-228 ◽  
Author(s):  
C. H. Popelar ◽  
T. Barber ◽  
J. Groom
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Experimental Method ◽  
Heat Sink ◽  
Thickness Distribution ◽  
Residual Stress Distribution ◽  
Least Square ◽  
Shear Stresses ◽  
Butt Weld

A combined analytical and experimental method for inferring the residual stresses in a pipe formed by joining two sections with a girth butt weld is described. The relieved surface strains due to cutting the pipe in two are measured and fitted in a least-square sense to the strains predicted by an analysis of the sectioned pipes. This permits a prediction of the through-thickness distribution of the residual longitudinal normal and radial shear stresses at the site of the cut. The procedure is used to infer the residual stress distribution due to last-pass-heat-sink welding of two sections of 16-in- (400-mm-) dia pipe.

scholarly journals The Contour Method for Residual Stress Determination Applied to an AA6082-T6 Friction Stir Butt Weld

2011 ◽  
Vol 681 ◽  
pp. 177-181 ◽  
Author(s):  
Valentin Richter-Trummer ◽  
Pedro Miguel Guimarães Pires Moreira ◽  
João Ribeiro ◽  
Paulo Manuel Salgado Tavares de Castro
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Cross Section ◽  
Residual Stress Distribution ◽  
Contour Method ◽  
Friction Stir Weld ◽  
Hole Drilling ◽  
Butt Weld ◽  
Friction Stir

Residual stresses parallel to the welding direction on a cross-section of a 3 mm thick friction stir butt-welded aluminum alloy AA6082-T6 plate were determined using the contour method. A full contour map of longitudinal residual stresses on a weld cross section was determined in this way, revealing detailed information on the residual stress distribution in the inside of a friction stir weld, especially in the nugget zone. The typical M-shape, usually described for the residual stress distribution in friction stir welds, was found. The maximum residual stresses are below the yield strength of the material in the shoulder region and, outside of the welding region, low tensile and compressive residual stresses are responsible for the necessary stress equilibrium on the plane of interest. A comparison was made with the established incremental hole drilling technique on an equivalent plate for validation and good agreement of both techniques was obtained. The distribution, as well as the magnitude of the residual stresses measured by both techniques, is very similar, thus validating both the experimental and numerical procedures used for the contour method application, presented and discussed in the present paper.

Theoretical prediction of residual stresses induced by cold spray with experimental validation

2019 ◽  
Vol 15 (3) ◽  
pp. 599-616 ◽  
Author(s):  
Dibakor Boruah ◽  
Xiang Zhang ◽  
Matthew Doré
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Cold Spray ◽  
Residual Stress Distribution ◽  
Thermal Mismatch ◽  
Individual Layer ◽  
Content Type ◽  
Layer Height ◽  
Proposed Model

PurposeThe purpose of this paper is to develop a simple analytical model for predicting the through-thickness distribution of residual stresses in a cold spray (CS) deposit-substrate assembly.Design/methodology/approachLayer-by-layer build-up of residual stresses induced by both the peening dominant and thermal mismatch dominant CS processes, taking into account the force and moment equilibrium requirements. The proposed model has been validated with the neutron diffraction measurements, taken from the published literature for different combinations of deposit-substrate assemblies comprising Cu, Mg, Ti, Al and Al alloys.FindingsThrough a parametric study, the influence of geometrical variables (number of layers, substrate height and individual layer height) on the through-thickness residual stress distribution and magnitude are elucidated. Both the number of deposited layers and substrate height affect residual stress magnitude, whereas the individual layer height has little effect. A good agreement has been achieved between the experimentally measured stress distributions and predictions by the proposed model.Originality/valueThe proposed model provides a more thorough explanation of residual stress development mechanisms by the CS process along with mathematical representation. Comparing to existing analytical and finite element methods, it provides a quicker estimation of the residual stress distribution and magnitude. This paper provides comparisons and contrast of the two different residual stress mechanisms: the peening dominant and the thermal mismatch dominant. The proposed model allows parametric studies of geometric variables, and can potentially contribute to CS process optimisation aiming at residual stress control.

A Further Study of Residual Stresses in Circumferential Welds

1973 ◽  
Vol 95 (4) ◽  
pp. 238-242 ◽  
Author(s):  
S. Vaidyanathan ◽  
H. Weiss ◽  
I. Finnie
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Base Metal ◽  
Filler Metal ◽  
Residual Stress Distribution ◽  
Experimental Results ◽  
Circumferential Welds ◽  
Single Pass ◽  
Full Penetration

The residual stress distribution for a circumferential weld between cylinders was obtained in a prior publication for a full penetration, single pass weld with no variation of alloy content across the weld. In the present work the approach is extended to cover a wider variety of weld conditions. It is shown that the effects of multipass welds, partial penetration welds, and welds with filler metal differing greatly in properties from the base metal can approximately be taken into account. Experimental results are presented to support the proposed method of analysis.

Measurement of Residual Stresses within a PWR Swaged Heater Tube

2011 ◽  
Vol 70 ◽  
pp. 279-284 ◽  
Author(s):  
D.M. Goudar ◽  
Ed J. Kingston ◽  
Mike C. Smith ◽  
Sayeed Hossain
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Stress Measurement ◽  
Measurement Techniques ◽  
Residual Stress Distribution ◽  
Hole Drilling ◽  
Shear Stresses ◽  
Outer Diameter ◽  
Near Surface ◽  
Heater Tube

Frequent failures of the pressuriser heater tubes used in Pressurised Water Reactors (PWRs) have been found. Axial cracks initiating from the tube outer diameter have been detected in some tubes as well as the resulting electrical problems. Replacement of the heater tubes requires an undesirably prolonged plant shutdown. In order to better understand these failures a series of residual stress measurements were carried out to obtain the near surface and through-thickness residual stress profiles in a stainless steel pressuriser heater tube. Three different residual stress measurement techniques were employed namely, Deep-Hole Drilling (DHD), Incremental Centre Hole Drilling (ICHD) and Sachs’ Boring (SB) to measure the through thickness residual stress distribution in the heater tubes. Results showed that the hoop stresses measured using all three techniques were predominantly tensile at all locations, while the axial stresses were found to be tensile at the surface and both tensile and compressive as they reduce to small magnitudes within the tube. The magnitude of the in-plane shear stresses was small at all measurement depths at all locations. The various measurement methods were found to complement each other well. All the measurements revealed a characteristic profile for the through-thickness residual stress distribution.

scholarly journals Separation of the Formation Mechanisms of Residual Stresses in LPBF 316L

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1234
Author(s):  
Alexander Ulbricht ◽  
Simon J. Altenburg ◽  
Maximilian Sprengel ◽  
Konstantin Sommer ◽  
Gunther Mohr ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
Formation Mechanisms ◽  
Micro Computed Tomography ◽  
Solidification Shrinkage ◽  
Stainless Steel 316L ◽  
Heat Accumulation ◽  
Cooling Rates

Rapid cooling rates and steep temperature gradients are characteristic of additively manufactured parts and important factors for the residual stress formation. This study examined the influence of heat accumulation on the distribution of residual stress in two prisms produced by Laser Powder Bed Fusion (LPBF) of austenitic stainless steel 316L. The layers of the prisms were exposed using two different border fill scan strategies: one scanned from the centre to the perimeter and the other from the perimeter to the centre. The goal was to reveal the effect of different heat inputs on samples featuring the same solidification shrinkage. Residual stress was characterised in one plane perpendicular to the building direction at the mid height using Neutron and Lab X-ray diffraction. Thermography data obtained during the build process were analysed in order to correlate the cooling rates and apparent surface temperatures with the residual stress results. Optical microscopy and micro computed tomography were used to correlate defect populations with the residual stress distribution. The two scanning strategies led to residual stress distributions that were typical for additively manufactured components: compressive stresses in the bulk and tensile stresses at the surface. However, due to the different heat accumulation, the maximum residual stress levels differed. We concluded that solidification shrinkage plays a major role in determining the shape of the residual stress distribution, while the temperature gradient mechanism appears to determine the magnitude of peak residual stresses.

scholarly journals Influence of Welding Defects on Residual Stresses: Numerical Study

2014 ◽  
Vol 996 ◽  
pp. 506-511
Author(s):  
Intissar Frih ◽  
Pierre Antoine Adragna ◽  
Guillaume Montay
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Numerical Study ◽  
Stress Gradient ◽  
Residual Stress Distribution ◽  
Welded Structure ◽  
Critical Defect ◽  
Welding Defects ◽  
Residual Stress Gradient

This paper presents a study on the application of the finite element methods to predict the influence of a defect on the residual stress distribution in a T-welded structure. A defect is introduced in a numerical model firstly without residual stress to see its impact (size and position) on the stress distribution. Secondly the most critical defect (determined previously) is simulated with a residual stress gradient. The obtained results are useful for computation stress concentration factor due to weld residual stresses.

Measurement of Residual Stresses in a Circular Ring Using the Successive Cracking Method

1996 ◽  
Vol 118 (2) ◽  
pp. 217-223 ◽  
Author(s):  
K. J. Kang ◽  
S. Y. Seol
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Circular Ring ◽  
Outer Edge ◽  
Residual Stress Distribution ◽  
Ring Specimen ◽  
Element Analysis ◽  
Theoretical Derivation ◽  
Sectioning Method

A method which we describe as the “successive cracking method” for measuring residual stresses in a circular ring is presented. In this method, the residual stresses are evaluated using a fracture mechanics approach. The strains measured at a point on the outer edge of the ring as a crack is introduced and extended from the edge are used to deduce the residual stress distribution in the uncracked ring. Finite element analysis is carried out to examine the validity of the theoretical derivation. Experiments to measure the residual stresses in a steel ring specimen are done by the successive cracking method. For comparison purposes, the experimental results using the sectioning method are presented as well. The successive cracking method is shown to be valid, simple, and effective for measuring the two-dimensional residual stress distribution in an axisymmetric member.

Residual Stress Relief in the Aluminium Alloy 7075

2017 ◽  
Vol 905 ◽  
pp. 31-39 ◽  
Author(s):  
Jeremy S. Robinson ◽  
Christopher E. Truman ◽  
Thilo Pirling ◽  
Tobias Panzner
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Aluminium Alloy ◽  
Stress Relief ◽  
Residual Stress Distribution ◽  
Cold Compression ◽  
Heat Treated ◽  
Minimum Residual

The residual stresses in heat treated 7075 aluminium alloy blocks have been characterised using two neutron diffraction strain scanning instruments. The influence of uniaxial cold compression (1-10%) on relieving the residual stress has been determined. Increasing the magnitude of cold compression from 1 to 10% has been shown to have a beneficial effect on the residual stress distribution by reducing the range between the maximum and minimum residual stresses. The effect of over aging 7075 on residual stress has also been characterised using neutron diffraction and this was found to reduce the residual stress by 25-40%. A relationship between {311} peaks widths and amount of cold compression was also observed.

Experimental and Numerical Analysis of the Distribution of Residual Stresses Induced by Laser Shock Peening in a 2050-T8 Aluminium Alloy

2011 ◽  
Vol 681 ◽  
pp. 296-302 ◽  
Author(s):  
Neila Hfaiedh ◽  
P. Peyre ◽  
I. Popa ◽  
Vincent Vignal ◽  
Wilfrid Seiler ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Aluminium Alloy ◽  
Residual Stress Distribution ◽  
Laser Shock Peening ◽  
Treatment Technique ◽  
Laser Shock ◽  
X Ray Diffraction ◽  
Shock Peening

Laser shock peening (LSP) is an innovative surface treatment technique successfully applied to improving fatigue performance of metallic material. The specific characteristic of (LSP) is the generation of a low work-hardening and a deep compressive residual stresses mechanically produced by a laser-induced shock wave propagating in the material. The aim of this study is to analyse the residual stress distribution induced by laser peening in 2050-T8 aluminium alloy experimentally by the X-ray diffraction technique (method sin2Y) and numerically, by a finite element numerical modelling. A specific focus was put on the residual stress distribution along the surface of the impacted material.

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